Nutritionally rich foods to boost your immune system during chemo
Chemotherapy can be an effective but difficult cancer treatment for many cancer patients. The process chemotherapy uses to eliminate cancer cells from the body also affects a patient’s healthy cells,1 which can result in various side effects including nausea, digestive problems, fatigue, taste and appetite changes and mouth sores or dryness.2
Learn more about the side effects of chemotherapy and how to manage them here.
Chemotherapy also temporarily weakens your immune system, which can be one of the more difficult and problematic side effects.3 This is again caused by chemotherapy drugs working against any cells in your body, which are rapidly multiplying – including both cancer cells and some healthy cells too, such as those in your gut, mouth and bone marrow.3 Bone marrow is where most of your blood cells are created – including white blood cells, which are essential for fighting off infections and illness.4,5
When chemotherapy damages your bone marrow cells, you can no longer produce the same number of white blood cells. This makes it harder for your body to fight infections and compromises your immune system function.4,5
Fortunately, good nutrition can help to support your immune system during chemotherapy and cancer, making your treatment more manageable and reducing your risk of illness or complications along the way. Maintaining a healthy diet can improve your energy levels and strength, help you sustain a healthy weight, and reduce your risk of developing other health conditions or illnesses.
Eating well throughout treatment doesn’t have to be complicated, stressful or time-consuming! Keep reading for actionable advice and strategies to help boost your immunity during cancer treatment.
How does chemotherapy affect the immune system and your diet?
The cells making up your immune system act like a protective “wall” keeping out any enemies – like infections and illnesses. Your white blood cells act like guards, working to defend this wall against intruders. These cells can be found all over your body, including your gut. When chemotherapy drugs unintentionally damage them, it becomes easier for infections (or intruders) to get past your “guards” or white blood cells and attack your body.6
Chemotherapy can also affect your ability to eat normally and maintain your regular diet.7 The same damage to your healthy cells may result in nausea, diarrhea or constipation, fatigue, and changes to your appetite or tastes.8 Each of these side effects can make it difficult to eat a healthy, balanced diet – especially if the treatment affects your appetite or your sense of taste, making foods taste metallic or unpleasant. It can become difficult to meet your daily nutritional needs during chemotherapy as a result.
However, prioritising good nutrition can help to boost your immune system and reduce chemotherapy’s impact on your body’s ability to fight off infection.7 In fact, your diet can even help you manage some of these symptoms. Try the following tips:
- Low appetite: Try eating various small and nutritious meals or snacks throughout the day, instead of aiming to eat three big meals.9
- Constipation: Drink plenty of water and eat foods rich in soluble and insoluble fibre in your meals, such as nuts and seeds, beans, legumes and vegetables.9
- Diarrhoea: Stay hydrated. Drink lots of water and prioritise foods containing only soluble fibre – such as oats, barley and white rice.10
- Taste and smell changes: Don’t force yourself to eat foods which taste unpleasant. Add flavour to your meals with spices, marinades or herbs, and focus on eating enough – even if that means eating foods you wouldn’t normally choose.9
- Nauseous: If you’re feeling unwell, try using citrus, ginger or peppermint, alone or in drinks/meals, to settle your stomach. You can also sip on soda water or ginger ale. Stick to bland foods while the nausea persists, focusing on eating small meals or snacks often, rather than large main meals.9 Again, prioritise hydration!
As well as helping you manage side effects, nutrition plays a key role in supporting immune function during chemotherapy.
What makes some foods good for the immune system?
These immune-boosting nutrients (and the foods they’re found in) are important to include in your diet throughout chemotherapy and beyond, to support immune function, help manage side effects,9 and maintain your bodyweight and muscle mass so you can achieve greater results from your treatment.
Essential food groups to include to support immunity include:
Antioxidants, including vitamins A, C, E and K, support your immune system during chemotherapy by contributing to white blood cell function,11 and reducing inflammation in the body. Antioxidant-rich foods may potentially slow the growth of cancer cells and improve your treatment results. Foods rich in antioxidants include:
Vitamin C: Citrus fruits, capsicum and berries.10
Vitamin E: Nuts, seeds, and leafy greens.12
Beta-Carotene: Carrots, sweet potatoes and pumpkin.10
These nutrients are huge players when it comes to immunity, supporting white blood cell function and boosting your ability to fight off illness. They’re found in nuts, seeds, whole grains and seafood.11
Protein provides fuel for your body and immune system and supports the repair of your body’s cells – making it critical for healing and recovery.9 Protein is needed for your body to be able to produce immune cells and plays a key role in preventing illness and infection during treatment. It also helps maintain your muscle mass during cancer and chemotherapy, which is crucial for your overall recovery and the results13 you can achieve from treatment. Include lean sources of animal protein in your diet regularly, such as chicken or fish, as well as plant-based proteins (which contain the greatest quantities of vitamins and minerals), like beans, legumes, nuts and seeds.9
Staying hydrated facilitates the transport of important nutrients to your cells and the removal of toxins from the body so your immune system can function efficiently.14 It can also ease side effects like vomiting and nausea, diarrhea and constipation, and fatigue, improving your energy levels and ability to tolerate treatment.14
Your gut plays a crucial role in immune function. A healthy gut = a stronger immune system! Foods rich in prebiotics, like garlic, asparagus, onions, whole grains and bananas, act as food or fuel for good gut bacteria15, while probiotic-rich and fermented foods like kimchi, yoghurts containing added probiotics, kefir, sauerkraut and kombucha, add more “good bacteria” to the gut to achieve a healthy, balanced gut microbiota.16 Together, these nutrients help you digest and absorb the nutrients in your food more efficiently, reduce inflammation, and support your immune system so you can better fight illness or infection.15 Aim to include plenty of both pre- and probiotics in your diet.
The best immune-boosting foods to eat during chemo
Some of the most nutritious foods to eat during chemotherapy to support immunity include:
- Oats: A good source of carbohydrates, protein and fibre. The mild flavour and creaminess of oatmeal make it easy to eat if you’re struggling with nausea, mouth sores or a dry mouth.
- Avocados: A great source of energy and nutrients if you’re struggling with a reduced appetite. Their texture and versatility make avocados a great choice if you’re experiencing a dry mouth, constipation or mouth sores.
- Eggs: Eggs are a high-quality source of protein, healthy fats and energy. Their protein content can help maintain your muscle mass and support the repair of your body’s cells. The soft texture of eggs (no matter how they’re cooked) is good for patients with mouth sores. Make sure your eggs are cooked thoroughly to prevent food poisoning.
- Bone broth: If you’re experiencing taste changes, dry mouth, mouth sores or sensitivity, nausea or low appetite, bone broth is easy to consume, mineral-rich, and soothing.
- Nuts and seeds: An easy on-the-go snack providing a good source of healthy fats, antioxidants, zinc and selenium for immune support – as well as a little protein. Nuts and seeds are easy to add to oatmeal or other recipes, or try nut butter if you’re struggling with mouth sores.
- Leafy green vegetables: Broccoli, kale, Brussels sprouts and other dark green (cruciferous) veggies are rich in vitamin C and a good source of fibre, assisting with digestion and supporting gut health and immunity.
- Salmon and other fatty fish: Rich in omega-3 fatty acids to help combat inflammation.
- Yoghurt and fermented foods: Yoghurts containing added prebiotics and other fermented foods like kefir and kimchi help balance your gut and support immunity.
Remember, during chemotherapy many patients experience taste, smell and appetite changes.8 Some chemotherapy drugs can leave a metallic taste in your mouth, or result in damage to your taste buds, mouth sores or a dry mouth.17
It’s important to opt for foods which boost your immunity, of course, but also ones that taste and feel good in your mouth. Don’t force yourself to eat foods you find unappealing. Focus on consistently meeting your energy, protein and nutrient needs with foods you enjoy to support your immune system.6
What foods should you avoid during cancer treatment?
Certain foods can weaken your immune system or put you at risk of illness and infection during chemotherapy.6
Foods or food groups to minimise during treatment include:
Unpasteurised cheeses and dairy products may contain harmful bacteria, which can cause bacterial infection.18
Choose pasteurised dairy products, as these have been heated to a high temperature to kill any harmful bacteria.18
Raw or undercooked foods like eggs, fish (including sushi), chicken and meat can carry Salmonella bacteria – putting you at risk of foodborne illnesses.18
- Minimise meals or foods containing these ingredients, including homemade mayonnaise, Caesar dressing or hollandaise, cooked eggs with runny yolks, raw cookie dough, oysters, lightly cooked steak or fish, and deli meats.18
- Never use the same cutting board or knife for raw foods and other produce or cooked food.
- Store raw items separately in your fridge in sealed bags or packaging.18
Highly refined, processed or fried foods can contain excessive amounts of sugar or unhealthy oils, which can increase inflammation.9
Chemotherapy places stress on your liver – the same organ which processes alcohol.
- Alcohol is dehydrating and prevents your body from properly absorbing nutrients from your food.
- Minimise alcohol during treatment as much as possible.10
Thoroughly wash all fruit, vegetables and fresh produce before preparing, cooking or eating. These items can contain harmful pathogens or bacteria, putting you at risk of infection.9
How to create a healthy diet meal plan for cancer treatment
When planning your meals while undergoing chemotherapy, focus on including nutrient-dense, immune-supporting foods which cater to any changes in taste and appetite or other side effects you’re navigating. Incorporating nutritious foods into fast, simple meals can support your health and immunity during treatment.
If you’re struggling to meet your nutritional needs, ask your healthcare professional whether adding an oral nutrition supplement (ONS) like Fortisip®, on top of a healthy, balanced diet, is appropriate for you. Fortisip® is high in calories to help improve your body weight when you’re unwell or recovering from illness,19 and a good source of protein to support the maintenance of muscle mass.18 It can help you meet your daily nutritional needs when your usual diet is not enough,19 especially if you’re struggling with reduced appetite or changing tastes and preferences.
Below are meal or snack suggestions for a full day. Tweak and adjust these suggestions to suit your tastes and needs.
Morning
Oatmeal topped with banana, Greek yoghurt and honey: A good source of fibre, protein, energy and nutrients to support gut health, immune function and muscle maintenance.
Mid-morning snack
Nuts: A handful of almonds and/or walnuts is a great on-the-go snack requiring no preparation, and providing plenty of immune-supporting healthy fats and nutrients.
Hard boiled eggs: A good source of protein and healthy fat. Ensure your eggs are thoroughly cooked and refrigerated until you’re ready to eat them
Smoothies: An ideal snack if you’re experiencing taste or smell changes, low appetite, or mouth sores. Add nutrient-dense ingredients like nut butter, fruit and vegetables,
You can easily add Fortisip® to a variety of recipes like these.
Explore the product range here to find the option best suited to your needs and preferences, with the guidance of your healthcare professional.
Lunch
Grilled salmon with quinoa and steamed broccoli: A great source of carbohydrates, fibre, protein, healthy fats, and antioxidants to help you feel full, energised and nourished.
Pair it with bone broth for nutrient-dense hydration.
Afternoon snack
Avocado on whole grain toast: Providing healthy fats, fibre and carbohydrates for energy and digestive, gut and immune support, while helping you meet your energy needs.
Pair this snack with ginger tea to settle any nausea or discomfort you’re experiencing.
Dinner
A source of lean protein with roasted sweet potato and greens: While cancer patients generally require much more protein per day compared to healthy adults, very few people get as much as they need.* Nourishing your body and immune system with lean proteins like chicken, fish or tofu supports your body’s repair and recovery processes. Roasted sweet potatoes are a good source of carbohydrates, antioxidants and fibre, and mixed greens provide plenty of immune-supporting vitamins and minerals.
Try a small bowl of probiotic-enriched yoghurt topped with berries or nuts and honey for dessert. It’s full of protein, antioxidants, healthy fats and energy to further support your immunity.
Evening snack
If you’re struggling to meet your energy and nutrient needs throughout the day, try eating an evening snack before bedtime. Try a handful of seeds, or a date smothered in nut butter, accompanied by some herbal tea. Both options are full of immune-supporting nutrients and are easily digestible so you can enjoy them before bed without discomfort.
Simple and delicious recipes for cancer patients using Fortisip®
Looking for nutritious, simple recipes to help you support your immune system with ease? We’ve got you covered.
This vegetable frittata recipe is a great place to start, containing ingredients like eggs, spinach, capsicum and pumpkin which provide your body and brain with protein, antioxidants, fibre and a bunch of vitamins and minerals. It’s a straight-forward, quick immune-boosting recipe, and can be easily adapted if you’re navigating side effects like taste changes or mouth sores. Simply swap out the suggested vegetables for any alternatives you prefer!
Eating well at every stage of chemotherapy treatment
You’ll likely need to make some dietary adjustments throughout each stage of chemotherapy. This supports your body’s changing needs and helps manage any treatment side effects.3
Both cancer and chemotherapy place significant demands on your body. Research shows that eating a nutritious, healthy diet before, throughout and after treatment can help you enjoy a better quality of life, supporting your energy levels, strength and immune function, as well as improving your treatment results, recovery time and reducing the chances of your cancer returning.3
Here are the dietary adjustments and priorities to focus on in each stage of your treatment journey:
Focus on building up your nutrient stores – including many different nutrient-rich foods from each of the main food groups3 (vegetables and legumes/beans, fruits, cereals and grains, lean proteins, and dairy products or alternatives).21 Make sure you’re getting the energy and protein you need, to prevent any muscle or weight loss during treatment – this helps optimise the health results you’re able to achieve later on!
Now is a good time to reach out to your healthcare professional and ask them to connect you with a specialist dietitian for personalised dietary advice during your cancer journey. It’s also a great opportunity to plan ahead and pre-prepare some nutrient- and energy-dense meals to store in your freezer for days you don’t feel like cooking.3
Your main goal while undergoing treatment should be to meet your energy, protein and nutrient needs consistently. This often requires eating small, frequent meals throughout the day (rather than three main meals) to help manage nausea while allowing you to get the nutrients you need.3 If your tastes change, be flexible – don’t force yourself to eat foods you find unenjoyable.
Avoid alcohol and keep an eye out for any signs of malnutrition or weight loss – you may need to introduce foods containing more energy and/or protein to adequately support your body and immune system.3
Try to maintain your bodyweight and muscle mass post-treatment, as this can help speed up your recovery.3 Eat a variety of nutrient-dense foods and introduce some gentle exercise if you’re able, so you can begin to rebuild muscle and strength after your treatment.3
Once you’ve recovered from treatment and are no longer managing side effects, try to maintain a healthy weight and balanced diet. Stay active, limit or avoid alcohol, and regularly visit your healthcare professional for check-ups and ongoing support. Continuing to look after your body long after you finish treatment can help reduce the risk of your cancer returning, and allow you to enjoy a better quality of life!
Support and resources for cancer patients
Access additional support, resources and information tailored to whatever stage of the cancer and treatment journey you’re currently navigating at our Cancer Care Hub. You’re never alone, and there are always resources available to help you along the way – so don’t be afraid to reach out.
For further nutritional support, speak to your healthcare professional about introducing Fortisip® – an energy- and nutrient-rich oral nutrition supplement which can help you meet your daily nutrient needs when your usual diet is not enough.19
Fortisip® is a food for special medical purposes and must be used under medical supervision.
This is provided for informational purposes only. It does not replace the advice of a healthcare professional. Please consult your healthcare professional for tailored advice.
References:
1 – Cancer Council Australia. Chemotherapy [Internet]. [cited 2025 April 20]. Available from: https://www.cancer.org.au/cancer-information/treatment/chemotherapy
2 – Cancer Australia. Treatment side effects [Internet]. [cited 2025 May 01]. Available from: https://www.canceraustralia.gov.au/impacted-cancer/treatment/treatment-side-effects
3 – Cancer Council Victoria. Nutrition overview [Internet]. [cited 2025 May 02]. Available from: https://www.cancervic.org.au/get-support/living-with-cancer/nutrition/nutrition-overview
4 – Cancer Research UK. The immune system and cancer [Internet]. [cited 2025 May 02]. Available from: https://www.cancerresearchuk.org/about-cancer/what-is-cancer/body-systems-and-cancer/the-immune-system-and-cancer
5 – Better Health Channel. Bone marrow [Internet]. [cited 2025 April 30]. Available from: https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/bone-marrow
6- Cancer Council NSW. Lowered immunity [Internet]. [cited 2025 May 01]. Available from: https://www.cancercouncil.com.au/cancer-information/living-well/nutrition-and-cancer/treatment-side-effects-and-nutrition/lowered-immunity/
7 – Cancer Council NSW. Why eat well? [Internet]. [cited 2025 May 01]. Available from: https://www.cancercouncil.com.au/cancer-information/living-well/nutrition-and-cancer/why-eat-well/#benefits
8 – Cancer Council Victoria. Taste and smell changes [Internet]. [cited 2025 May 01]. Available from: https://www.cancervic.org.au/cancer-information/treatments/common-side-effects/taste-and-smell-changes
9 – Johns Hopkins Medicine. Cancer diet: foods to add and avoid during cancer treatment [Internet]. [cited 2025 May 03]. Available from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/cancer/cancer-diet-foods-to-add-and-avoid-during-cancer-treatment
10 – Breastcancer.org. Tips for eating during chemotherapy [Internet]. [cited 2025 May 01]. Available from: https://www.breastcancer.org/managing-life/diet-nutrition/healthy-eating-during-treatment/tips-eating-during-chemotherapy
11 – Stanford Health Care. Antioxidants as part of your cancer diet [Internet]. [cited 2025 May 02]. Available from: https://stanfordhealthcare.org/medical-clinics/cancer-nutrition-services/reducing-cancer-risk/antioxidants.html
12 – Zhang Y, et al. Role of antioxidant vitamins and other micronutrients on regulation of immunity and inflammation. Int J Mol Sci. 2023;24(6):6092.
13 – MD Anderson Cancer Center. 6 easy protein sources for cancer patients [Internet]. [cited 2025 May 01]. Available from: https://www.mdanderson.org/cancerwise/6-easy-protein-sources-for-cancer-patients.h00-159699912.html
14 – MD Anderson Cancer Center. Cancer treatment side effects: dehydration [Internet]. [cited 2025 May 03]. Available from: https://www.mdanderson.org/cancerwise/cancer-treatment-side-effect–dehydration.h00-159305412.html
15 – Harvard Health Publishing. Prebiotics: understanding their role in gut health [Internet]. [cited 2025 April 30]. Available from: https://www.health.harvard.edu/nutrition/prebiotics-understanding-their-role-in-gut-health
16 – Mayo Clinic. Probiotics: what you need to know [Internet]. [cited 2025 April 29]. Available from: https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/probiotics/faq-20058065
17 – Cancer Council NSW. Side effects of chemotherapy [Internet]. [cited 2025 May 01]. Available from: https://www.cancercouncil.com.au/cancer-information/cancer-treatment/chemotherapy/side-effects/
18 – Healthline. Foods to avoid while on chemo [Internet]. [cited 2025 May 01]. Available from: https://www.healthline.com/health/cancer/foods-to-avoid-while-on-chemo
19 – Hickman I, et al. Evidence based practice guidelines for the nutritional management of malnutrition in adult patients across the continuum of care. Nutr Diet. 2009;66:S1–34.
20 – Food Standards Australia New Zealand. Schedule 4 – Nutrition, health and related claims [Internet]. Canberra: FSANZ; [cited 2025 May 02]. Available from: https://www.foodstandards.gov.au/business/labelling/nutrition-health-and-related-claims
21 – Healthdirect Australia. What is a balanced diet? [Internet]. [cited 2025 May 01]. Available from: https://www.healthdirect.gov.au/balanced-diet#:~:text=about%20other%20foods?-,What%20is%20a%20balanced%20diet?,milk%2C%20cheese%2C%20yoghurt%20or%20alternatives
